UV light for chameleons

Keeping chameleons in captivity failed in the past due partly to a limited understanding of their need for ultra violet light. Sadly, the situation has only improved slightly today and the need for UV light for chameleons is too often ignored.

I still get photos of Veiled chameleons with chronic MBD from owners who thought they could get away without a UV light. They write to ask how they can ‘fix’ their pet’s MBD. In most, if not all, cases they can’t.

The correct use of UV light is essential for a healthy chameleon. But it may not be as straightforward as you think. Read on to learn why distance and strength can play a critical part.

Know your UV

UV light for chameleons showing wavelength
UV light wavelength compared to other light

There are three types of ultra violet light: UV-A (long wave), UV-B (medium wave) and UV-C (short wave).

UV-A is part of the chameleon’s visible spectrum. It allows it to see its surroundings in a slightly different way to humans but it is UV-B that is important for vitamin D3 synthesis in reptiles. UV-B has a wavelength in the range of 290 to 320nm (nanometres).

UV-C is harmful and is used in ultra violet sterilisers.

The process of vitamin D3 synthesis in the skin as a result of exposure to ultra violet light involves complex topics such as PTH (parathyroid) hormones and pre-vitamin D3 conversion.  As such, these are outside the scope of this blog. It’s enough to repeat: UV light is essential for a healthy chameleon. It’s also crucial if a female is to lay viable eggs.

Generally, a UV light for chameleons does not produce heat. It should not be confused with other types of lighting, such as basking or Infra-Red lights.

The sun – the perfect UV light for chameleons

The cheapest source of UV-B is the sun. This is obviously far better than any artificial source.  Anyone who has read any of my books or blogs elsewhere will know I’m a huge advocate of exposing chameleons to natural sunlight. But only in the right location and situation. Obviously, you must exercise common sense how you expose your chameleon. And not all climates are suitable.

Even a few hours outdoors each week will be beneficial.  In South Africa, it was my habit to place my chameleons outside as much as possible, even in the winter.  Unless the temperatures were below 16°C, I would put my Panther chameleons outside against a sunny wall and out of any cold winds during the middle of the day.

In Malaysia, I keep my adult Veiled chameleons outside 24 hours a day. However, the cages are placed so they get a mix of sun and shade. Daytime temperatures in the open can reach 36°C but inside the cages it rarely goes above 32°C.

The cages house small bushes so the chameleons can crawl among the leaves to escape the sun if they wish. An automated watering system helps keep the bottom of the cage moist and at a lower temperature, even on hot days.

Not all species would be survive outside in a hot, tropical climate.

There are subtle differences in behaviour under artificial light compared to natural sun light.  Studies show that in the wild chameleons can regulate their ultra violet light exposure, moving in and out of the sun as required.

How much UV is natural?

Under artificial light, there is evidence that some species are attracted to the ultra violet light a bit like moths. This may mean they do not regulate their exposure as they would in the wild.

This is not necessarily as bad as it sounds when one compares outside UV and that from a UV light using a UV meter.  On a sunny day at noon in Gauteng, a UV meter might read 450 mW/cm2. This may be reduced by cloud or by taking the reading earlier or later in the day but it is still quite intense.

UV light for chameleons showing wavelength
UV light emission from a 5.0 ReptiGlo UV light.

It is worth noting that the altitude on the Highveld (between 1,500 and 1,700 metres above sea level) results in meter readings higher than at sea level. At lower altitudes a reading of 300mW/cm2 might be normal at noon on the equator.  For comparison, a 5.0 ReptiGlo UV light for chameleons will register roughly 17 mW/cm2 at 30 cm from the tube.

Does this comparison mean that either a stronger light is needed indoors or that artificial light is ineffectual? No. If used correctly artificial light can be quite sufficient and beneficial. Using a stronger light would probably result in health issues, including eye damage.

UV Strength

The key thing to remember is the strength of the light falls off with distance from the source.  The following chart for a 5.0 UV tube, shows this clearly:

Strength of the UV as distance from the light  increases
Distance in cm 5 10 15 20 25 30 35 40 45 50
mW/cm2 100 54 37 28 22 17 14 13 11 9


From this chart it can be seen that at 30cm the strength of the light is 17 mW/cm2.  Research and experience show this is an acceptable reading for captive chameleons.

But the chart shows the further down the cage the chameleon travels away from the light source, the lower the ultra violet intensity. By 50cm the light is barely producing any worthwhile UV light.

UV lights for chameleons when they are small
UV lights above baby chameleons. Note the ends overlap to make up for reduced UV.

Another point to bear in mind is that the last few centimetres at each end of the tube produce far less UV than the middle. Therefore, always use the longest tube you can for your cage.

The majority of UV lights on sale in South Africa as tubes normally have an effective lifespan of about nine months. I’ve tested several with a UV meter during use and found some still producing ultra violet at full strength several months after this. However, unless you’ve invested in a UV meter it’s better to assume that nine months is the limit.


If you’re planning on keeping a chameleon, it is essential you invest in UV lighting. If you skimp on this you will end up with a sick chameleon. The only alternative is exposure to direct natural sunlight.

Keeping a chameleon in a window will not work. When the sun hits the window, the temperatures in the chameleon cage are likely rise very quickly. Never put a glass cage outdoors, even with the lid off.

Most types of glass filter out the UV light for chameleons. That means that most conservatories and glasshouses will not work unless special glass is used.

The information shown above is for the ‘normal’ chameleons kept in captivity, e.g. Veiled, Panther, Carpets, etc.  Veiled chameleons are especially prone to MBD and poor UV light is often a direct cause.

There are species that are not as dependent on UV, for example, certain Brookesias that spend their time on the forest floor. Montane species may come from areas with intense cloud cover but when it breaks, the altitude can mean the UV intensity is high. A normal UV set up should be used unless you find evidence to show the species has specific requirements.

UV light for chameleons is essential to avoid MBD
Chameleon suffering severe MBD due to lack of UV lighting


Choosing the best cage for your chameleon

There is a great opportunity for housing a chameleon in a cage that is a focal point and an object of beauty in your house. Be warned: getting the best chameleon cage involves planning and expense!

Whatever cage you decide on must be escape proof. Chameleons are master escapologists. Your plump Veiled will have no difficulty in compressing laterally and slipping through a narrow gap.

Once the chameleon has disappeared you may not see him again. A chameleon can run at a surprising speed and if it reaches the garden the chances of recovery are slim.  Just as easily, crickets can squeeze through small holes. So, an insect proof cage is also desirable to avoid a house overrun with chirping insects.

Size is important

The size of the cage for your chameleon depends on your budget, the type of chameleon, the space available in your home and other factors described below.  Don’t forget to take into account the age of your chameleon.

Juveniles will not do well in big cages. Depending on the layout, it’s surprisingly easy for a small chameleon to starve in a large cage. By nature, smaller chameleons are more cautious and will tend to hide. They often stay higher in the cage, so placing food low in the cage or out in the open, could mean it’s ignored. Pygmy chameleons and neonates will be discussed in a later post. For now, let’s focus on the adults of true chameleons.

Adult True Chameleons

The variation and possibilities for housing an adult chameleon are nearly endless.  To avoid costly mistakes, consider the following before designing a little piece of the rainforest in your living room. (Not least of which is – does you chameleon really come from rain forest?)

The following basic requirements must be met.

The housing must be:

  • well ventilated
  • escape proof
  • allow for ultraviolet light
  • allow for temperature management
  • have suitable drainage.

Once these are in place, your imagination can run riot.

Unless the chameleon cage you use is very large, it should only contain one adult chameleon.  It may look like your pair of Veiled chameleons are getting along well but it is an unnatural situation and one or both of them will become stressed.

Glass Cages

Glass can create many problems in a chameleon cage:

  • Ventilation issues
  • Lime scale
  • Reflections
  • Damage to the tongue
  • Poor drainage

Let’s consider these one at a time.


One of the biggest killers (aside from the lack of UV) in the early days was poor ventilation. At that time, everyone assumed high humidity reflected the natural conditions in the wild. This is only true for a limited number of species. Veiled, Panthers, Carpet chameleons and many others need good ventilation. Poor ventilation will lead to respiratory problems.

Glass cages are difficult to ventilate properly. There are some very large cages, often custom built, that utilise glass and have excellent ventilation. But many do not.

Lime scale

If you’re spraying your chameleon sufficiently, you are likely to end up with lime scale on the glass. That’s the nasty white crust that builds up quickly from hard water but can result from anything except distilled. It’s unattractive and hard to remove.


glass chameleon cage
Reflections can be a big problem with glass cages

Glass will reflect an image of the chameleon back into the cage. This may cause it to use a variety of display stances and colours to make the ‘intruder’ leave its territory.  Obviously, the reflected ‘intruder’ will match each display exactly.  Stress will result.

It is possible to place the cage and lights in ways to minimise the reflection but if it’s not done well, you will have problems. A few species are not anti-social but Veiled and Panther chameleons will not be happy.

Tongue Damage

If the glass is kept very clean, the chameleon will not see it. A fly landing on the outside of the cage will get ‘shot’ but the unforgiving nature of the glass may, in rare cases, damage the tongue.

Poor drainage

Many glass cages have glass bases and are sealed around the base. If the chameleon cage is sprayed with enough water several times a day, the bottom of the cage will be deep in water! Making holes in the base is possible but not without the risk of cracking the base.

Does that mean I can’t use glass?

Where possible, I would say ‘no to glass’. However, I have kept chameleons in the UK and used glass-fronted cages. I have friends with various species that also use glass due to the climate there.

In such cases, these are glass cages designed for reptiles. An old fish tank is not the same thing and will lead to all sorts of problems.

In climates where it is essential to provide heating, for many enthusiasts it’s not practical to heat a room and use net cages. A glass cage is the only option. With care and planning, a glass cage can provide effective housing. It would never be my first choice but it would silly to ignore them.

Netting Cages

Flexarium as netting as a chameleon cage
Netting cages may not be attractive but they are easy to move around.

The cages I have used very successfully over many years are netting cages covering a light plastic tubular frame. The ones I use are Exo Terra flexariums but other brands sell equally good versions.

The benefits of these netting cages are:

  • good ventilation,
  • they allow ultraviolet light
  • good drainage for heavy spraying
  • light enough to carry outdoors when the weather permits
  • easily cleaned
  • available in a variety of sizes (although not so much with Exo Terra these days).

The negative factors of these cages are

  • they can be expensive
  • they are not attractive indoors
  • the netting is not strong enough to stop crickets chewing
  • the zips can prove troublesome after a while.

Furthermore, it is important to remember the netting stops about 40% of the UV light passing through.  Despite these drawbacks, I have found them to be the ideal cage for the chameleons that are available in South Africa and Malaysia.

Other types of chameleon cage

Bird cages

In desperation, I once used a large parrot cage as a makeshift home for an unexpected Meller’s chameleon. I did not like the thin bars.  This is due to the danger that the chameleon will start to climb the thin wires but be unable to maintain its footing and fall.  I also found that the chameleon rubbed its nose on the wire.

Other people, however, have used a similar style of cage for large Veiled chameleons with some success. I would avoid using these as a cage for your chameleon if possible.


Aviary as a chameleon cage
Aviary set up for chameleons

During the summer an aviary can be used to good effect.  I have bred Veiled chameleons in an aviary, keeping one male and several females together without any signs of aggression or stress.  The aviary I used was 4 metres long by 2 metres wide. I put lots of different plants in the cage. This gave a lot of space for each chameleon to hide from others or to go through the mating cycle in almost natural conditions.

I have bred Veiled chameleons in an aviary, keeping one male and several females together without any signs of aggression or stress.  The aviary I used was 4 metres long by 2 metres wide. And it was heavily planted in the centre. This gave a lot of space for each chameleon to hide from others or to go through the mating cycle in almost natural conditions.

When using an aviary there are certain factors that should be considered.  In South Africa, birds can pose a problem. I lost a large male Jackson’s chameleon that was attacked through the wire by weaver birds.  When I opened the aviary door to rescue the chameleon the birds actually flew inside the aviary to continue their assault!  I suspect this was unusual as it has not happened with any chameleons since and I have kept several species quite happily in the same aviary.

I placed a piece of shade netting across the top of the aviary to protect against heavy hail or rain.


Whatever style of chameleon cage you choose, ensure that it has proper drainage to prevent water logging and excessively high humidity. And it should be easy to clean.

There is little point in having an elaborate well-planted cage, mimicking the rain forests of Uganda if you cannot clean it easily and it poses a health risk to your chameleon. But that raises the same question as at the beginning – does your chameleon come from the rain forests of Uganda. Probably not.

Therefore, it’s important to do research about the conditions found in the chameleon’s natural location. Find out how other people have set up their cages.

Finally, don’t forget other considerations such as UV light, the strength of which falls off alarmingly, and the provision of water. I will cover these in later posts.

Any comments, thoughts or suggestions are welcome.